American firms including Waltham (from its Roxbury and Waltham predecessors) and later Elgin, Illinois and Hamilton pioneered machine production of interchangeable watch parts from the 1850s onward, building on techniques already proven in firearms manufacture. Their pitch was consistency and price: a factory watch did not depend on a single craftsman's hand-fitting.
The 1876 Philadelphia Centennial Exhibition is often cited as the moment Swiss observers recognised the scale of the American achievement, and the resulting alarm fed into serious Swiss self-examination, notably the 1876 report associated with the Swiss delegation. Treat the exhibition as a catalyst that crystallised existing concerns rather than the sole cause of change.
Swiss établissage — the distributed system of specialist ébauche makers, finishers and assemblers — was not simply displaced by American-style vertical factories. Instead it adapted: firms mechanised specific stages, standardised callibres across établisseurs, and organised quality control (culminating much later in bodies overseeing chronometer certification) without abandoning the distributed structure entirely.
American manufacturers had real advantages in scale and capital for a period, but they were vulnerable to the same forces they had exploited: economic downturns, and eventually foreign competition on price, hit the large single-site factories hard, while the more distributed Swiss system could contract and expand production across many smaller firms.
By the early twentieth century the picture had reversed: several major American factories closed or were absorbed, while Swiss production expanded internationally, aided also by the American market's own growing appetite for imported wristwatches after the First World War.
For collectors the rivalry period matters because it is precisely dated by known events (the 1876 exhibition, subsequent factory reports, closures and mergers on both sides), which makes it one of the more reliably documented chapters in industrial watchmaking history, in contrast to older and more anecdotal narratives about individual makers.